1. Field of the Invention
The present invention relates to a scroll compressor, and in particular to a scroll compressor which is capable of simplifying a structure of a valve, decreasing a size of a whole compressor and lowering a noise occurred in the valve by reducing the number of construction parts.
2. Description of the Prior Art
Generally, compressors can be divided into various kinds in accordance with compression methods, among them an air conditioning system required to be small-sized and lightweight mainly uses a scroll compressor.
FIG. 1 is a sectional view illustrating a scroll compressor in accordance with the prior art.
The scroll compressor in accordance with the prior art includes a casing 106 respectively connected to a suction pipe 102 at which a fluid is sucked, a discharge pipe 104 at which a compressed fluid is discharged and having a hermetically sealed certain space, a driving unit 108 placed at the lower portion of the casing 106 and generating a driving force, and a compressing unit 110 placed at the upper portion of the casing 106, connected to the driving unit 108 by a rotational shaft 112, compressing the fluid sucked through the suction pipe 102 and discharging it through the discharge pipe 104 by the rotation of the rotational shaft 112.
A supporting frame 114 is installed inside the casing in order to support the rotational shaft 112 rotatively and support the compressing unit 110, and a separation panel 120 is installed inside the casing 106 in order to divide the inner space of the casing 106 into a first chamber 116 putting a low pressure on a fluid and a second chamber 118 putting a high pressure on the fluid.
Because the driving unit 108 is constructed with a stator 122 fixed to the casing 106 and a rotor 124 installed to the inner circumference of the stator 122 and fixed to the rotational shaft 112, when power is applied to the stator 122, the rotor 124 is rotated by the mutual operation of the stator 122 and the rotor 124, accordingly the rotational shaft 112 is rotated.
The compressing unit 110 includes a fixed scroll 128 formed with a fixed vane 126 having an involute shape and fixed to the separation panel 120, and an orbiting scroll 132 formed as an orbiting vane 130 having an involute shape corresponding to vane 126 so as to have a certain compression space between the fixed vane 126 of the fixed scroll 128, supported by the supporting panel 114 so as to perform an orbiting motion and orbiting in the rotation of the rotational shaft 112.
A discharge passage 136 is formed at the center of the fixed scroll 128 in order to discharge the fluid compressed by the mutual operation of the fixed scroll 128 and the orbiting scroll 132 into the second chamber 118, a check valve 138 is installed to the upper portion of the discharge passage 136 in order to prevent the fluid discharged into the second chamber 118 from flowing backward into the first chamber 116, and a vacuum preventive valve 140 is installed to the side of the fixed scroll 128 in order to prevent the first chamber 116 from being in a vacuum state by flowing the fluid of the second chamber 118 to the first chamber 116 when the driving unit 108 is stopped or the suction pipe 102 is closed.
The check valve 138 is constructed with a valve body 142 combined to the central upper end portion of the fixed scroll 128 at which the discharge passage 136 is formed by a bolt and having a penetrated central portion so as to connect to the discharge passage 136, and a piston type valve member 144 installed inside the valve body 142 so as to be movable up and down in order to close the discharge passage 136 by a self weight.
In the check valve 138, when the fluid compressed by the mutual operation of the fixed scroll 128 and the orbiting scroll 132 is discharged into the discharge passage 136, the valve member 144 is lifted by a pressure of the discharged fluid. Herein, the compressed fluid flows into the second chamber 118 while the discharge passage 136 is opened and is discharged outside through the discharge pipe 104.
As depicted in FIG. 2, the vacuum preventive valve 140 includes a cylinder unit 150 formed at the side of the fixed scroll 128 so as to have a certain space, a valve spool 152 installed to the inner circumference of the cylinder unit 150 so as to be slidable, and an elastic member 158 engaged between the side surface of the valve spool 152 and the internal wall of the cylinder unit 150 and providing a certain elastic force to the valve spool 152.
Herein, the side of the cylinder portion 150 is opened so as to connect with the first chamber 118. And, the fluid compressed at the compression space between the fixed vane 126 and the orbiting vane 130 flows into the cylinder unit 150 through a first flow channel 154, and because the cylinder unit 150 is connected to the second chamber 118 by a second flow channel 156, the fluid inside the second chamber 118 flows into the cylinder unit 150.
A spring constant of an elastic member 158 is smaller than a pressure of the fluid flowing into the first flow channel 154.
In the vibration preventive valve 140, when the fluid compressed in the compression space puts to the side of the cylinder unit 150 through the first flow channel 154 and operates on the valve spool 152, the valve spool 152 is moved in the right direction in FIG. 2 by overcoming the elastic force of the elastic member 158, accordingly the closed state of the second flow channel 156 can be maintained.
In the closed state, when the operation of the orbiting scroll 132 is stopped due to the stopping of the driving unit 108, as depicted in FIG. 3, a hydraulic pressure acting on the valve spool 152 through the first flow channel 154 is removed, the valve spool 152 is moved in the left direction in FIG. 3 by the elastic force of the elastic member 158. Herein, because the second flow channel 156 and the first chamber 116 are connected by the movement of the valve spring 152, the high pressure fluid inside the second chamber 118 flows into the first chamber 116, accordingly the first chamber 116 and the second chamber 118 can keep a balance pressure.
And, when the driving unit 108 is operated in the closed state of the suction pipe 102, the hydraulic pressure acting on the valve spool 152 through the first flow channel 154 is removed, the valve spool 152 is moved in the left direction in FIG. 2, then, the second flow channel 156 and the second chamber 118 are connected each other, the fluid inside the second chamber 118 is supplied to the first chamber 116, accordingly it is possible to prevent the first chamber from being in a vacuum state.
However, in the conventional scroll compressor, because a check valve preventing a backward flow of a fluid and a vacuum preventive valve preventing a first chamber from being in a vacuum state are respectively installed to a fixed scroll, the structure is complicate, and because the two valves are respectively installed to the fixed scroll, a space for housing the valves has to be increased, accordingly the size of a whole compressor is increased.
In addition, because the structure of the compressor is complicate due to the vibration preventive valve and the check valve, production processes are intricate, accordingly a production cost is increased.
In addition, because a valve member of the check valve is formed as a piston type, the valve member is moved up and down inside the valve body in accordance with a pressure of a fluid, when a discharge pressure is unstable, the valve member generates a noise by being collided with the internal wall of the valve body or the upper surface of the fixed scroll.
In order to solve the above-mentioned problems, it is an object of the present invention to provide a scroll compressor which is capable of simplifying a structure of a valve, decreasing a size of a whole compressor and reducing a production cost by having a function for preventing a fluid from flowing backward and a function for preventing a compressor from being a vacuum state simultaneously with one valve.
It is another object of the present invention to provide a scroll compressor which is capable of lowering a noise occurred in a valve due to an unstable state of a discharge pressure of a fluid in the operation of the compressor.
In order to achieve the above-mentioned objects, a scroll compressor in accordance with the present invention comprises a casing having a hermetically sealed certain space divided into a first chamber at which a fluid is sucked and a second chamber at which a compressed fluid is discharged, a driving unit housed inside the casing and generating a driving force, a compressing unit including a fixed scroll and an orbiting scroll connected to the driving unit by a rotational shaft in order to compress and discharge the fluid when the driving unit is operated, and a valve assembly rotatively installed to the upper surface of the fixed scroll, opening/closing a discharge hole at which the compressed fluid is discharged and opening/closing a passage connecting the first chamber and the second chamber each other.
An inner diameter of the passage is smaller than an inner diameter of the discharge hole.
The valve assembly is constructed with a rod part hinge-connected to the fixed scroll and curved at a certain angle in two directions centering around a hinge-connected point, a hinge part formed between the rod part and the upper surface of the fixed scroll and supporting the rod part rotatively, a first valve part formed at the end of the rod part and opening/closing the discharge hole and a second valve part formed at the other end of the rod part and opening/closing the passage.
The rod part is rotatively installed to the upper surface of the fixed scroll by the hinge part and has a plate shape curved at a certain angle in two directions centering around the hinge part.
The hinge part is constructed with a hinge bracket perpendicularly projected from the upper surface of the fixed scroll and having a hinge hole at which a hinge pin is inserted and a hinge protrusion upwardly projected from the curved portion of the rod part and having a hinge hole at which the hinge pin is inserted.
The first valve part is extended from one end of the rod part and is formed as a circular flat plate shape in order to open/close the discharge hole.
The first valve part is formed so as to have a diameter greater than an inner diameter of the discharge hole.
The second valve part is extended from the other end of the rod part and is formed as a circular flat plate shape in order to open/close the passage.
The second valve part is formed so as to have a diameter greater than an inner diameter of the passage.